note_screen.dart

import 'package:flutter/material.dart';
import 'package:firebase_database/firebase_database.dart';

import 'package:flutter_crud/model/note.dart';

class NoteScreen extends StatefulWidget {
  final Note note;

  NoteScreen(this.note);

  @override
  _NoteScreenState createState() => _NoteScreenState();
}

final noteReference = FirebaseDatabase.instance.reference().child('notes');

class _NoteScreenState extends State<NoteScreen> {
  TextEditingController _titleController;
  TextEditingController _descriptionController;

  @override
  void initState() {
    // TODO: implement initState
    super.initState();

    _titleController = TextEditingController(text: widget.note.title);
    _descriptionController =
        TextEditingController(text: widget.note.description);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Note'),
      ),
      body: Container(
        margin: EdgeInsets.all(15.0),
        alignment: Alignment.center,
        child: Column(
          children: <Widget>[
            TextField(
              controller: _titleController,
              decoration: InputDecoration(labelText: 'Title'),
            ),
            Padding(padding: EdgeInsets.all(5.0)),
            TextField(
              controller: _descriptionController,
              decoration: InputDecoration(labelText: 'Description'),
            ),
            Padding(padding: EdgeInsets.all(5.0)),
            RaisedButton(
              child: (widget.note.id != null) ? Text('Update') : Text('Add'),
              onPressed: () {
                if(widget.note.id != null) {
                  noteReference.child(widget.note.id).set({
                    'title': _titleController,
                    'description': _descriptionController
                  }).then((_) {
                    Navigator.pop(context);
                  });
                } else {
                  noteReference.push().set({
                    'title': _titleController.text,
                    'description': _descriptionController.text
                  }).then((_) {
                    Navigator.pop(context);
                  });
                }
              },
            ),
          ],
        ),
      ),
    );
  }
}